Can the tyres be stored as usual after the tyre change?

Tyres can be stored as usual.

In the event of a flat, can an SSR tyre also be “repaired”?

SSR tyres which have been damaged or driven flat are not repairable and should not be put back into service.

Can both SSR tyres and standard tyres be used on the same vehicle?

SSR tyres should not be mixed with standard tyres on the same car - even if paired on the axles (in exceptional cases, a normal tyre can be used for a limited period and distance. Then of course, the driver has to be clearly advised that normal tyres do not have the run-flat characteristics of SSR).